Integral ductwork diffuser

ABSTRACT

Apparatus and a corresponding method for forming from a strip of sheet metal stock material a length of spiral duct that includes an integral diffuser. A perforator forms perforations in the strip at at least selected intervals. A machine forms the strip, after perforation, into spiral seamed duct.

CROSS-REFERENCE TO PROVISIONAL PATENT APPLICATION

[0001] The benefit of U.S. Provisional Patent Application Ser. No.60/254,103, filed Dec. 8, 2000, is claimed.

BACKGROUND OF THE INVENTION

[0002] The invention relates to air diffusers employed in combinationwith round spiral and flat oval ductwork, such as is employed inheating, ventilation and air conditioning (HVAC) system applications.

[0003] Round, thin-walled spiral seamed metal ducts made from strips ofsheet metal are widely employed in heating and air conditioninginstallations, as well as in other air ducting installations. Suchspiral duct is efficiently produced in desired lengths by Tubeformermachines, manufactured for example, by Spiral-Helix, Inc. of BuffaloGrove, Ill., and described for example in Castricum U.S. Pat. Nos.4,567,742; 4,706,481 and 4,711,110. Another machine for producing spiralseamed pipe is disclosed in Price et al U.S. Provisional PatentApplication Ser. No. 60/264,387, filed Jan. 26, 2001. Another machinefor producing spiral seamed pipe is disclosed in Price et al U.S.Provisional Patent Application Ser. No. 60/264,387, filed Jan. 26, 2001.Spiral duct has a number of advantages, in both ease of installation andperformance.

[0004] Typically, a strip of sheet metal 5.394 inches (137 mm) wide issupplied to the Tubeformer machine. An initial stage of the Tubeformermachine comprises a set of flange forming rolls which prepare the edgesof the strip for subsequently formed spiral lock seams. Thereafter, thestrip is rolled into formed spiral lock seams. Thereafter, the strip isrolled into the desired spiral duct size, and the spiral lock seams arecompleted.

[0005] In some installations limited space prevents the use of roundspiral duct. Accordingly, flatter ductwork which is oval incross-section is employed, also known as flat oval. As the tube formermachines produce round and not oval ductwork, a separate machine, knownas an ovalizer, is ordinarily employed to form round ductwork to oval. Asuitable ovalizer is disclosed in Price et al U.S. Pat. No. 6,000,260.

[0006] Air diffusers are typically employed at appropriate locationsalong the length of a spiral duct, either round or flat oval. A typicalconventional practice is to install a grill box. A typical grill boxtakes the form of a rectangular box, open at the front and back,attached to the spiral ductwork at the location of a correspondingrectangular cutout in the ductwork, and a grill attached. Thus, afour-step operation is required: (1) The ductwork is manufactured. (2) Ahole for the grill box is cut. (3) The grill box is fabricated andinstalled, secured either by welding or by sheet metal screws. (4)Finally, a suitable grill is purchased and installed.

[0007] A variation, which avoids the need for the separate grill box, isto directly attach a semi-cylindrical grill to the side of a spiralduct, over a rectangular opening. An example is a Duct-D-Fuser™ grill,manufactured by McGill Air Flow Corporation of Groveport, Ohio. In thisvariation, three steps are required: (1) Manufacture the ductwork. (2)Cut a hole for the perforated grill. (3) Purchase and install the grill.

SUMMARY OF THE INVENTION

[0008] In an exemplary embodiment, apparatus for forming from a strip ofsheet metal stock material a length of spiral duct that includes anintegral diffuser includes a perforator forming perforations in thestrip at at least selected intervals, and a machine for forming thestrip, after perforation into spiral seamed duct.

[0009] A corresponding method for forming a length of spiral duct thatincludes an integral diffuser embodying the invention includes the stepsof providing a strip of sheet metal stock material, perforating thestrip at at least selected intervals, and employing a machine to formthe strip into spiral seamed ducts.

BRIEF DESCRIPTION OF THE DRAWINGS

[0010]FIG. 1 is a three dimensional view of apparatus embodying theinvention;

[0011]FIG. 2 is a conceptual diagram depicting the operation of oneembodiment;

[0012]FIG. 3 is a plan view of a perforator;

[0013]FIG. 4 is a side view of a portion of the FIG. 3 perforator;

[0014]FIG. 5 is a conceptual view, similar to that of FIG. 2, depictinganother embodiment of the invention;

[0015]FIG. 6 is a side view of another apparatus embodying theinvention, including a stationary punch assembly; and

[0016]FIG. 7 is a representation of an exemplary punching pattern.

DESCRIPTION

[0017] Embodiments of the invention eliminate the separate grill andgrill box by perforating the sheet metal stock as part of the spiralforming operation, either before or after the flange forming rolls.

[0018]FIG. 1 shows an apparatus 20 embodying the invention. A strip ofsheet metal stock material 22 enters the apparatus 20 as indicated byarrow 24. Spiral seamed duct 26, including an integral diffuser 28, isproduced by the apparatus.

[0019] The apparatus 20 more particularly includes a perforator 30 forforming perforations in the strip 22 at at least selected intervals,such as the perforations 52. Various forms of perforator 30 aredescribed in greater detail hereinbelow. Following the perforator is amachine, generally designated 34, for forming a strip into the spiralseamed duct 26. The machine includes a flange forming roller station 36,a passive feed section 38, and a bending roller station 40, including aseaming roller. The particular machine 34 illustrated is disclosed inthe above-referenced Price et al U.S. Provisional Application Ser. No.60/264,387. However, the machine 34 may just as well be a Tubeformermachine, such as is disclosed in the above-referenced Castricum U.S.Pat. Nos. 4,567,742; 4,706,481 and 4,711,110. The apparatus 20additionally includes a controller 42 for coordinating the operation ofthe perforator 30 and of the spiral duct-forming machine 34.

[0020] During operation, and under the control of the controller 42, theperforator 30 forms clusters of perforations, such as the perforations52, at intervals corresponding to the circumference of the spiral seamedduct 26 being formed. The resultant diffuser 28 formed has a widthcorresponding to several strips.

[0021] With reference to FIG. 2, conceptually illustrated is theoperation of one embodiment of apparatus 20, including the perforator 30and spiral-forming machine 34. Thus, the strip 22 of sheet metal entersthe apparatus 20. In a spiral-forming zone 60 the sheet metal strip 22is wound to form the spiral duct 26. At 62 spiral lock seams are formed,all as is known in the art.

[0022] In embodiments of the invention, in a perforation zone 64perforations are formed in the sheet metal strip 22, in an appropriatepattern, as represented by separate clusters 66, 68 and 70. The clusters66, 68 and 70 of perforations are appropriately located, under thedirection of the controller 42, such that, upon formation of the spiralductwork, a desired grill or diffuser pattern, as is represented at 28results.

[0023] Any suitable process may be employed for making the perforationclusters 66, 68 and 70.

[0024] With reference to the plan view of FIG. 3 and the side view ofFIG. 4, an exemplary device embodying the invention for forming theperforations takes the form of a rolling punch, generally designated 80.The rolling punch 80 includes a punching roll 82 and an opposed die roll84, with the strip 22 of sheet metal stock passing between.

[0025] In FIG. 3, a motor 86 drives the punching roll 82 through agearing reducer 88, under the control of a suitable electroniccontroller 90.

[0026] The motor 86 and thus the punching roll 82 is programmed to beengaged when required, and make the necessary size perforation for theapplication.

[0027] Referring again to FIG. 2, the perforation cluster 68 extends allthe way across the sheet metal strip 22, while the perforation clusters66 and 70 extend only part way across. To form the perforation clusters66 and 70 extending only part way across, in an exemplary embodiment thepunching roll 82 is arranged, by means of a splined drive shaft 92 andan actuating cylinder 94 to move transversely so that the punch roll 82punches only a portion of the width of the sheet metal strip 22.

[0028] With reference to FIG. 5, conceptually illustrated is theoperation of another apparatus 100 embodying the invention. FIG. 6illustrates the apparatus 100 in elevational view.

[0029] In FIG. 6 the apparatus 100 includes the machine 34 for formingspiral metal duct as is described herein above with reference to FIGS. 1and 2. In FIG. 6 as a matter of convenience, the controller 42 is withinthe machine 34.

[0030] The apparatus 100 includes a perforator in the form of astationary punch 102, including a set of servo-driven feed rolls 104,and a stationary punch assembly 106, including a punch 108 driven by anhydraulic cylinder 110, and a corresponding die block 112. FIG. 8illustrates an exemplary punching pattern of the stationary punch 106.Each cycle of the punch 106 produces 11 perforations, arranged in tworows. A typical perforation diameter is {fraction (5/16)} inch.

[0031] Movement of the strip 22 must be interrupted for punching, whilethe spiral duct forming machine 34 proceeds relatively continuously.Accordingly, an idle loop 114 is formed by the strip 22, prior toentering the spiral duct-forming machine 34.

[0032] It will be appreciated that embodiments of the invention allowthe grill or perforation to be automatically installed into the ductworkduring the fabrication phase of the ductwork. The ductwork is simplysent to a job site, and is installed without any additional labor ormaterial cost.

[0033] Alternatively, mobile apparatus can be employed at the job siteto perforate a strip of sheet metal stock material and form spiralseamed ductwork.

[0034] The punching system can also be used to fabricate ductwork forsound attenuation or 360° perforated diffusers. Conventionally,attenuation ductwork is ordered prepunched from a steel mill. Thispre-punched steel costs more than solid steel, and requires thefabricator to stock two different types of metal. Embodiments of theinvention permit the perforated product to be made on the same machine,without buying special stock.

[0035] In a sequence of operation, a machine operator receives an orderfor ductwork, with diffuser locations specified. The operator thenprograms the machine via the controller 40, which is programmable, tolocate a perforated section of ductwork at the predetermined location.

[0036] As the machine begins operation, coiled sheet metal stock 22 isfed into the machine, and proceeds through the flange forming rollersand through the perforation zone until it is received by the spiralforming zone, where the spiral ductwork is actually formed.

[0037] When portions of the sheet metal stock material which are to bepunched proceed through the perforation zone 64, the punching wheel 82or punch assembly 102 is activated to punch the material for theresultant perforated ductwork.

[0038] While specific embodiments of the invention have been illustratedand described herein, it is realized that numerous modifications andchanges will occur to those skilled in the art. It is therefore to beunderstood that the appended claims are intended to cover all suchmodifications and changes that fall within the true spirit and scope ofthe invention.

What is claimed is:
 1. Apparatus for forming from a strip of sheet metal stock material a length of spiral duct that includes an integral diffuser, said apparatus comprising: a perforator for forming perforations in the strip at at least selected intervals; and a machine for forming the strip, after perforation, into spiral seamed duct.
 2. The apparatus of claim 1, wherein said perforator forms clusters of perforations at intervals corresponding to the circumference of the spiral seamed duct being formed.
 3. The apparatus of claim 1, wherein said perforator comprises a punching roll.
 4. The apparatus of claim 1, wherein said perforator comprises a stationary punch.
 5. The apparatus of claim 1, which further comprises a controller connected for coordinating operation of said perforator and of said machine for forming the strip into spiral seamed duct.
 6. Apparatus for forming, from a strip of sheet metal stock a length of 360° perforated spiral duct, said apparatus comprising: a perforator for forming perforations in the strip in a continuous manner and a machine for forming the strip, after perforation, into spiral seamed duct.
 7. A method for forming a length of spiral duct that includes an integral diffuser, said method comprising: providing a strip of sheet metal stock material; perforating the strip at at least selected intervals; and employing a machine to form the strip into spiral seamed duct.
 8. The method of claim, which comprises perforating the strip to form clusters of perforations at intervals corresponding to the circumference of the spiral seamed duct being formed. 